Abnormalities of the seminal tract causing infertility: diagnosis with endorectal sonography.

Endorectal sonography, developed primarily for use in the diagnosis and staging of prostatic carcinoma, should be the first imaging technique used in the evaluation of an infertile man with low semen volume in whom either a hypoplastic or obstructed seminal tract is suspected. Endorectal sonography allows visualization of the seminal vesicles, which are otherwise difficult to examine. We used endorectal sonography to evaluate six young men, five of whom were being evaluated for azoospermia and infertility. One patient had no identifiable seminal vesicle on either side. Four patients had unilateral absence of the seminal vesicles. Of these four, three had a sonographically normal-appearing seminal vesicle on the contralateral side, and the fourth had an obstructed system contralaterally. The sixth patient had a hypoplastic system on the left and an obstructed system on the right. The delineation of an obstructed or agenetic seminal vesicle and seminal tract on endorectal sonography allows decisions to be made regarding treatment and prognosis.